1. Field of the Invention
The present invention relates to wooden structural members. More specifically, the present invention relates to a fabricated composite structural member including two parallel wooden rails having wood and foam spacing elements between them for use in building construction either as a beam or vertical wall stud.
2. Prior Art
Known building structural members include I-beams with metal webs, or with wood or laminated wooden webs. Various types of foam have been used for insulation.
Patent Cooperation Treaty publication No. WO 81/00585 discloses a girder with two parallel wood beams joined by a spacing element of polyurethane foam. The foam binds the two beams together, but separated by a distance which is adapted to the desired depth for the web of the girder.
Various wooden I-beam structures are also known in which a structural member has parallel wooden beams joined by a wooden web, such as those disclosed in U.S. Pat. Nos. 1,377,891; 4,336,678; 3,490,188; 4,195,462 and 4,191,000. The advantage of such structures is that they provide the structural strength of solid lumber while utilizing smaller dimensions of wood, thus conserving valuable wood supplies. Such I-beam structures may be used, for example, in frame house construction.
None of the known I-beam structures have contemplated the use of polyurethane foam to increase the structural strength of the structural member in addition to adding valuable insulating properties.